Some vehicles include brake systems that operate based on pressure differentials in fluid disposed in the brake systems. For example, air brakes in some vehicles (e.g., rail vehicles) may disengage when the air pressure in the air brakes is decreased. The air brakes in such vehicles may be released in certain environments in order to perform operations on the vehicles. The air brakes in rail vehicles, for example, may be disengaged while in a rail yard in order to more freely roll the rail vehicles around within the rail yard.
In order to disengage the air brakes of vehicles, a human operator may pull on a lever that opens a valve of the air brakes. The valve is opened and the air within the brake system is bled (e.g., the air flows out of the brake system) to reduce the pressure within the brake system and disengage the air brakes. Use of human operators in a rail yard, however, is not without problems. The operations taking place in a rail yard pose safety risks to the human operators. Additionally, the use of human operators can involve increased cost relative to automated systems.
But, automated systems pose problems as well. Automated systems may be unreliable due to the wide variances in the brake systems among several different vehicles. For example, different vehicles may have brake levers in different locations that may be difficult for the automated system to locate, may have brake levers that require different amounts of force to actuate, may have other components that block movement of the automated system when attempting to access and pull the brake lever, may have brake levers that become temporarily stuck, etc. These variances can make it difficult for an automated system to perform brake bleeding operations.